Why are AI predictions so terrible?

In 1997, IBM's Deep Blue beat world chess champion Gary Kasparov, the first time an AI technology was able to outperform a world expert in a highly complicated endeavor. It was even more impressive when you consider they were using 1997 computational power. In 1997, my computer could barely connect to the internet; long waits of agonizing beeps and buzzes made it clear the computer was struggling under the weight of the task. Even in the wake of Deep Blue's literally game-changing victory, most experts remained unconvinced. Piet Hut, an astrophysicist at the Institute for Advanced Study in New Jersey, told the New York Times in 1997 that it would still be another hundred years before a computer beat a human at Go. Admittedly, the ancient game of Go is infinitely more complicated than chess.